Format

Send to

Choose Destination
Curr Biol. 2016 Jul 25;26(14):1929-34. doi: 10.1016/j.cub.2016.05.065. Epub 2016 Jun 30.

A Representation of Effort in Decision-Making and Motor Control.

Author information

1
Laboratory for Computational Motor Control, Department of Biomedical Engineering, Johns Hopkins School of Medicine, 410 Traylor Building, 720 Rutland Avenue, Baltimore, MD 21205, USA.
2
Neuromechanics Laboratory, Department of Integrative Physiology, University of Colorado, 354 UCB, Boulder, CO 80309-0354, USA.
3
Neuromechanics Laboratory, Department of Integrative Physiology, University of Colorado, 354 UCB, Boulder, CO 80309-0354, USA. Electronic address: alaa.ahmed@colorado.edu.

Abstract

Given two rewarding stimuli, animals tend to choose the more rewarding (or less effortful) option. However, they also move faster toward that stimulus [1-5]. This suggests that reward and effort not only affect decision-making, they also influence motor control [6, 7]. How does the brain compute the effort requirements of a task? Here, we considered data acquired during walking, reaching, flying, or isometric force production. In analyzing the decision-making and motor-control behaviors of various animals, we considered the possibility that the brain may estimate effort objectively, via the metabolic energy consumed to produce the action. We measured the energetic cost of reaching and found that, like walking, it was convex in time, with a global minimum, implying that there existed a movement speed that minimized effort. However, reward made it worthwhile to be energetically inefficient. Using a framework in which utility of an action depended on reward and energetic cost, both discounted in time, we found that it was possible to account for a body of data in which animals were free to choose how to move (reach slow or fast), as well as what to do (walk or fly, produce force F1 or F2). We suggest that some forms of decision-making and motor control may share a common utility in which the brain represents the effort associated with performing an action objectively via its metabolic energy cost and then, like reward, temporally discounts it as a function of movement duration.

PMID:
27374338
DOI:
10.1016/j.cub.2016.05.065
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center